References of "Nys, Gilles-Antoine"
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See detailNew 3D standards and perspectives
Nys, Gilles-Antoine ULiege; Billen, Roland ULiege

Scientific conference (2020, September 22)

Presentation of the last developments of the 3D Standard of the OGC Family: CityGML 3.0 and CityJSON.

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See detailUliège activities related to CityJSON
Nys, Gilles-Antoine ULiege

Scientific conference (2020, September 17)

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See detailCityJSON Building Generation from Airborne LiDAR 3D Point Clouds
Nys, Gilles-Antoine ULiege; Poux, Florent ULiege; Billen, Roland ULiege

in ISPRS International Journal of Geo-Information (2020), 9(521),

The relevant insights provided by 3D City models greatly improve Smart Cities and their management policies. In the urban built environment, buildings frequently represent the most studied and modeled ... [more ▼]

The relevant insights provided by 3D City models greatly improve Smart Cities and their management policies. In the urban built environment, buildings frequently represent the most studied and modeled features. CityJSON format proposes a lightweight and developer-friendly alternative to CityGML. This paper proposes an improvement to the usability of 3D models providing an automatic generation method in CityJSON, to ensure compactness, expressivity, and interoperability. In addition to a compliance rate in excess of 92% for geometry and topology, the generated model allows the handling of contextual information, such as metadata and refined levels of details (LoD), in a built-in manner. By breaking down the building-generation process, it creates consistent building objects from the unique source of Light Detection and Ranging (LiDAR) point clouds. [less ▲]

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See detailAutomatic 3D Buildings Compact Reconstruction from LiDAR point clouds
Nys, Gilles-Antoine ULiege; Billen, Roland ULiege; Poux, Florent ULiege

in International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences (2020, August 12), (XLIII-B2-2020), 473-478

Point clouds generated from aerial LiDAR and photogrammetric techniques are great ways to obtain valuable spatial insights over large scale. However, their nature hinders the direct extraction and sharing ... [more ▼]

Point clouds generated from aerial LiDAR and photogrammetric techniques are great ways to obtain valuable spatial insights over large scale. However, their nature hinders the direct extraction and sharing of underlying information. The generation of consistent large-scale 3D city models from this real-world data is a major challenge. Specifically, the integration in workflows usable by decision-making scenarios demands that the data is structured, rich and exchangeable. CityGML permits new advances in terms of interoperable endeavour to use city models in a collaborative way. Efforts have led to render good-looking digital twins of cities but few of them take into account their potential use in finite elements simulations (wind, floods, heat radiation model, etc.). In this paper, we target the automatic reconstruction of consistent 3D city buildings highlighting closed solids, coherent surface junctions, perfect snapping of vertices, etc. It specifically investigates the topological and geometrical consistency of generated models from aerial LiDAR point cloud, formatted following the CityJSON specifications. These models are then usable to store relevant information and provides geometries usable within complex computations such as computational fluid dynamics, free of local inconsistencies (e.g. holes and unclosed solids). [less ▲]

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See detailPotential for urban greening with green roofs: A way towards smart cities
Joshi, Mitali ULiege; Selmi, Wissal ULiege; Binard, Marc ULiege et al

Scientific conference (2020)

Cities are experiencing increased pressure on social, economic, and environmental sectors due to the rapid urbanisation and increasing risk owing to climate change affecting the urban environment ... [more ▼]

Cities are experiencing increased pressure on social, economic, and environmental sectors due to the rapid urbanisation and increasing risk owing to climate change affecting the urban environment. Solutions such as green roofs are often discussed in the context of smart and sustainable cities as they present a multi-functional and solution-oriented approach to address these challenges. Green roofs become extremely relevant in the context of highly urbanised and compact cities where impervious surfaces are abundant. Therefore, in this paper, we analyse the potential of green roofs at a city scale with the help of parameters such as area and slope of the roof and structure of the building. We also identify the priority zones based on environmental and socio-economic parameters. The study is carried out in the city of Liege, Belgium. The results suggest that around 20% (350 hectares) of the total buildings in the city have the potential for developing green roofs. Moreover, the potential of green roofs is quite significant in terms of roof area in the priority zone. Due to significant socio-economic deprivation in high priority zones, implementation of green roofs might not be affordable. Buildings with larger roof sizes are mostly owned by ompanies or commercial establishments, thus, making larger roofs more relevant for retrofitting green roof. Thus, our approach can act as a preliminary decision-making tool for urban planners to analyse the potential of green roofs and prioritize them in deprived areas. [less ▲]

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See detailIntegration of multiple sensor data into a 3D GIS for cities monitoring
Kasprzyk, Jean-Paul ULiege; Nys, Gilles-Antoine ULiege; Billen, Roland ULiege

Conference (2019, October 18)

This research is part of a larger project, called “Ecocity Tools”, which aims to establish environment and energy diagnostics for cities at the neighborhood scale. Experts in different fields provide ... [more ▼]

This research is part of a larger project, called “Ecocity Tools”, which aims to establish environment and energy diagnostics for cities at the neighborhood scale. Experts in different fields provide information based on both scientific models (climatology, pollutant dispersions) and sensor data (energetic cadaster, air quality) to a 3D GIS for decision support in urban planning. This paper focuses on two interconnected problematics about the use of GIS in a “Smart City” approach: an appropriate 3D geometric model and the integration of sensor data into this model. As buildings can be equipped by several sensors in multiples locations (rooms, floors, walls, etc), information should be attachable to specific geometric parts (like walls). It is thus important for 3D city models to be adapted to detailed scale levels. Thanks to the consideration of different levels of details (LoD), from buildings footprints (LoD 0) to interiors (LoD 4), the CityGML standard (OGC) can theoretically fit any 3D application. Nevertheless, these data are not always available at very detailed levels. For example, Belgian authorities deliver open data in CityGML LoD 2 (representing buildings as volumes with simplified roof shapes) for important cities like Brussels or Namur. Therefore, this paper proposes a PostGIS data model able to attach information to specific building parts even in poorly detailed city models (LoD 1 or 2). The second part of this research is the implementation of other OGC standards specifically for the visualization of sensor data into a GIS: Sensor Observation Service (SOS) and SensorThings API (STA). As Web Feature Service (WFS) does for geographical features, SOS allows any compatible GIS client to import georeferenced sensor data and metadata through a simple http request (including filters on space, time and other attributes). More recently, STA, in addition to SOS functions, supports JSON format for data exchanges and also provides a “Tasking Part”: the STA server is able to ask sensors and actuators to do specific tasks like “start/stop measurements”. In this research, a SOS server, able to communicate with the 3D GIS, is implemented thanks to the open source tool provided by 52North. [less ▲]

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See detailA Semantic Retrieval System for Remote Sensing Web Platforms
Nys, Gilles-Antoine ULiege; Kasprzyk, Jean-Paul ULiege; Hallot, Pierre ULiege et al

Conference (2019, June 13)

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See detailA Semantic Retrieval System for Remote Sensing Web Platforms
Nys, Gilles-Antoine ULiege; Kasprzyk, Jean-Paul ULiege; Hallot, Pierre ULiege et al

in International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences (2019, June 05), XLII-2(W13), 1593-1599

This paper proposes a solution to reduce the semantic gap between final users and data/processing providers in a web market place dedicated to remote sensing products. Nowadays, search engine are common ... [more ▼]

This paper proposes a solution to reduce the semantic gap between final users and data/processing providers in a web market place dedicated to remote sensing products. Nowadays, search engine are common tools on the Internet. Users are accustomed to use them and used to get tabular classification of provided answers. These smart agents are set up to answer basic questions using automatic pages redirection or chitchat. In this research, to ensure coherence between user’s requests and platform answers, natural language processing algorithms and knowledge graphs are integrated within a web platform thanks to a NoSQL graph database connected to open thesauri and Geographic Information Systems (GIS). Therefore, the most pertinent services can be proposed based on input sentences including non-technical vocabulary but also geographical components (the user interface includes a text area and an interactive map). While processing chains and remote sensing ontologies were presented in one of our previous studies, this article focuses on natural languages algorithms and knowledge mining. [less ▲]

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See detailGIS 3.0 : Towards a new generation of Geographic Information Systems
Nys, Gilles-Antoine ULiege

Conference given outside the academic context (2019)

New problems need new solutions. In a world where spatial data are not only a resource but also a product, Geographical Information Systems do have a role. This presentation will develop avenues for ... [more ▼]

New problems need new solutions. In a world where spatial data are not only a resource but also a product, Geographical Information Systems do have a role. This presentation will develop avenues for reflection in order to best meet the new challenges that arise. [less ▲]

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See detailSpatio-temporal reasoning in CIDOC CRM: an hybrid ontology with GeoSPARQL and OWL-Time
Nys, Gilles-Antoine ULiege; Van Ruymbeke, Muriel ULiege; Billen, Roland ULiege

in CEUR Workshop Proceedings (2018, October 13), 2230

Semantic description of cultural heritage information is already widely structured through CIDOC CRM and its different extensions. This shared understanding of cultural heritage information has already ... [more ▼]

Semantic description of cultural heritage information is already widely structured through CIDOC CRM and its different extensions. This shared understanding of cultural heritage information has already proved its usefulness. Until now, despite its spatial and temporal data management proposition, lack standardization limited the possibilities in terms of reasoning and workability. This paper proposes to increase the potentiality offered by the current scheme by including GeoSPARQL and OWL-Time in the framework. The result, as hybrid ontology, allows concurrent spatial and temporal handling. These are used to provide a near-full data management for complex spatio-temporal reasoning and querying through SPARQL queries. Example queries depicting the strength of the approach and allowing knowledge discovery in huge archaeological datasets illustrate its benefits [less ▲]

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See detailTOWARDS AN ONTOLOGY FOR THE STRUCTURING OF REMOTE SENSING OPERATIONS SHARED BY DIFFERENT PROCESSING CHAINS
Nys, Gilles-Antoine ULiege; Kasprzyk, Jean-Paul ULiege; Hallot, Pierre ULiege et al

in International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences (2018, September 19), XLII(4), 483-490

This paper proposes an ontology to structure and describe processing chains in the remote sensing field. These chains are made up of elementary elements (operations) organized in collections. The ... [more ▼]

This paper proposes an ontology to structure and describe processing chains in the remote sensing field. These chains are made up of elementary elements (operations) organized in collections. The collection notion, including information about order and repeatability of the elements, is widely defined by using the relations between their constituting items and relations to the whole data store. Applications of the ontology are illustrated with web services provided by a platform for users and providers of processing chains. A graphical interface facilitates data integration in a RDF triple store. Thanks to the management of metadata (ISO19115-3), relevant information can be requested by intelligent search engines. Graph analysis, errors management and consistency rules are computed in order to gather coherent information from the different sources. Results of these analyses are then used by machine learning algorithms for new knowledge discovery. [less ▲]

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See detail3D Point Cloud Semantic Modelling: Integrated Framework for Indoor Spaces and Furniture
Poux, Florent ULiege; Neuville, Romain ULiege; Nys, Gilles-Antoine ULiege et al

in Remote Sensing (2018), 10(9), 1412

3D models derived from point clouds are useful in various shapes to optimize the trade-off between precision and geometric complexity. They are defined at different granularity levels according to each ... [more ▼]

3D models derived from point clouds are useful in various shapes to optimize the trade-off between precision and geometric complexity. They are defined at different granularity levels according to each indoor situation. In this article, we present an integrated 3D semantic reconstruction framework that leverages segmented point cloud data and domain ontologies. Our approach follows a part-to-whole conception which models a point cloud in parametric elements usable per instance and aggregated to obtain a global 3D model. We first extract analytic features, object relationships and contextual information to permit better object characterization. Then, we propose a multi-representation modelling mechanism augmented by automatic recognition and fitting from the 3D library ModelNet10 to provide the best candidates for several 3D scans of furniture. Finally, we combine every element to obtain a consistent indoor hybrid 3D model. The method allows a wide range of applications from interior navigation to virtual stores. [less ▲]

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See detailLa transition numérique dans le domaine du patrimoine bâti: un retour d'expériences
Billen, Roland ULiege; Jonlet, Benoît ULiege; Luczfalvy Jancsó, Andrea ULiege et al

in Bulletin de la commission royale des monuments, sites et fouilles - Tome 30 (2018)

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See detailSpatio-temporal reasoning in CIDOC CRM: an hybrid ontology with GeoSPARQL and OWL-Time
Nys, Gilles-Antoine ULiege; Van Ruymbeke, Muriel ULiege; Billen, Roland ULiege

Conference (2018, August 28)

Semantic description of cultural heritage information is already widely structured through CIDOC CRM and its different extensions. This shared understanding of cultural heritage information has already ... [more ▼]

Semantic description of cultural heritage information is already widely structured through CIDOC CRM and its different extensions. This shared understanding of cultural heritage information has already proved its usefulness. Until now, despite its spatial and temporal data management proposition, lack standardization limited the possibilities in terms of reasoning and workability. This paper proposes to increase the potentiality offered by the current scheme by including GeoSPARQL and OWL-Time in the framework. The result, as hybrid ontology, allows concurrent spatial and temporal handling. These are used to provide a near-full data management for complex spatio-temporal reasoning and querying through SPARQL queries. Example queries depicting the strength of the approach and allowing knowledge discovery in huge archaeological datasets illustrate its benefits [less ▲]

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See detailImplementation of multiple interpretation data model concepts in CIDOC CRM and compatible models
Van Ruymbeke, Muriel ULiege; Hallot, Pierre ULiege; Nys, Gilles-Antoine ULiege et al

in Virtual Archaeology Review (2018), 9(19), 50-65

Modelling cultural heritage is a research topic shared by a broad scientific community. Although this subject has been widely studied, it seems that some aspects still have to be tackled. This paper ... [more ▼]

Modelling cultural heritage is a research topic shared by a broad scientific community. Although this subject has been widely studied, it seems that some aspects still have to be tackled. This paper describes two CIDOC Conceptual Reference Model (CRM) extension proposals (A & B) dedicated to structuring knowledge concerning historical objects and historical events. It focuses on multiple interpretations and sequential reality, this last being a concept which does not exist in CIDOC CRM but was originally developed in another conceptual model, the Multiple Interpretation Data Model (MIDM). To begin, an extensive description of MIDM concepts is given as well as a recall of its main peculiarities. It is followed by a mapping proposed to translate MIDM concepts into ontologies devoted to describe cultural heritage entities and activities, the CIDOC-CRM and compatible models. Unfortunately, some MIDM concepts are not covered by this mapping because they do not match with existing CRM entities and properties, and this paper explains why an extension is necessary. It describes how the two versions of the extension proposal cover the missing MIDM concepts. One of these two versions, the proposal A, has been implemented as an ontology in Protégé and has been tested through an instantiation phase using a real example. This instantiation phase is fully detailed. It shows that proposal A works coherently with CRM ontologies. On another hand, instantiation phase highlights improvements needs such as recording chronology in a structured way. [less ▲]

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See detailFusion de données lasergrammétriques/photogrammétriques et techniques d'extraction d'information archéologique sur base de nuage de points 3D
Poux, Florent ULiege; Billen, Roland ULiege; Hallot, Pierre ULiege et al

Conference (2018, March 08)

While virtual copies of the real world tend to be created faster than ever in the form of point clouds and derived products, their use by all professionals requires new tools to facilitate the ... [more ▼]

While virtual copies of the real world tend to be created faster than ever in the form of point clouds and derived products, their use by all professionals requires new tools to facilitate the dissemination of knowledge. Digital analyses are changing the way researchers, archaeologists and heritage curators work and collaborate to gradually combine their expertise through a common platform. Nevertheless, the addition of semantic information to complete the point clouds is essential to allow a complete use as reference data. There are few concepts and tools that simplify this process, making it difficult to share analyses. Different methods will be presented to extract archaeological information from the point clouds and create a connection with the structured knowledge in the form of ontology. Classification and structuring procedures for reasoning from the data will be discussed. These methodologies will be illustrated at the Germigny-des-prés (France) and Château de Jehay (Belgium) sites. The communication and 3D visualization tools developed to allow several interactions will also be presented. While the Germigny-des-prés site (France) is almost exclusively dedicated to research, the same is not true for the Jehay site. This exceptional site belongs to the Province of Liège and is managed by a non-profit association. A partnership has been established between this association and the Geomatics Unit of the University of Liège. It concerns not only the acquisition of 3D data but also the support of the association in its archaeological research, site rehabilitation and enhancement projects. Several measurement campaigns were carried out at different stages of the renovation. New missions are planned, notably by students from the University. In addition to several promotional videos and a few derivative products useful for renovation, a virtual reality operation is currently attracting the attention of our developers. Indeed, the Castle is currently largely closed to the public, it is planned this summer to offer virtual reality tours based on lasergrammetric and photogrammetric surveys. In the longer term, it is planned to establish a spatialized information system dedicated to the Castle; the conceptual bases of this system have already been established during a recent study. [less ▲]

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See detailEO_Regions_Science: Basic Research in support of EO_Regions!
Orban, Anne ULiege; Barbier, Christian ULiege; Billen, Roland ULiege et al

Conference (2018, January)

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See detail3D Point Clouds in Archaeology: Advances in Acquisition, Processing and Knowledge Integration Applied to Quasi-Planar Objects
Poux, Florent ULiege; Neuville, Romain ULiege; Van Wersch, Line ULiege et al

in Geosciences (2017), 7(4), 96

Digital investigations of the real world through point clouds and derivatives are changing how curators, cultural heritage researchers and archaeologists work and collaborate. To progressively aggregate ... [more ▼]

Digital investigations of the real world through point clouds and derivatives are changing how curators, cultural heritage researchers and archaeologists work and collaborate. To progressively aggregate expertise and enhance the working proficiency of all professionals, virtual reconstructions demand adapted tools to facilitate knowledge dissemination. However, to achieve this perceptive level, a point cloud must be semantically rich, retaining relevant information for the end user. In this paper, we review the state of the art of point cloud integration within archaeological applications, giving an overview of 3D technologies for heritage, digital exploitation and case studies showing the assimilation status within 3D GIS. Identified issues and new perspectives are addressed through a knowledge-based point cloud processing framework for multi-sensory data, and illustrated on mosaics and quasi-planar objects. A new acquisition, pre-processing, segmentation and ontology-based classification method on hybrid point clouds from both terrestrial laser scanning and dense image matching is proposed to enable reasoning for information extraction. Experiments in detection and semantic enrichment show promising results of 94% correct semantization. Then, we integrate the metadata in an archaeological smart point cloud data structure allowing spatio-semantic queries related to CIDOC-CRM. Finally, a WebGL prototype is presented that leads to efficient communication between actors by proposing optimal 3D data visualizations as a basis on which interaction can grow. [less ▲]

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See detailLiDAR aérien et autres nuages de points pour la cartographie multi-échelles
Poux, Florent ULiege; Neuville, Romain ULiege; Kasprzyk, Jean-Paul ULiege et al

Conference (2017, September 12)

Utilisation de nuage de points pour la cartographie 3D multi-échelles. Exemples d'utilisation et définition de workflows pour assurer l'interopérabilité lors de la fusion de données issues de différents ... [more ▼]

Utilisation de nuage de points pour la cartographie 3D multi-échelles. Exemples d'utilisation et définition de workflows pour assurer l'interopérabilité lors de la fusion de données issues de différents capteurs. [less ▲]

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